Air pollution is the introduction of chemicals, particulate matter, or biological materials that cause harm or discomfort to humans or other living organisms, or cause damage to the natural environment or built environment, into the atmosphere. A substance in the air that can cause harm to humans and the environment is known as an air pollutant. Pollutants can be in the form of solid particles, liquid droplets, or gases. In addition, they may be natural or man-made.
Major primary pollutants produced by human activity include: Sulfur oxides (SOx) Nitrogen oxides (NOx) Carbon monoxide Carbon dioxide (CO2) Volatile organic compounds - VOCs Particulate matter - Ammonia Chlorofluorocarbons (CFCs) Toxic metals, such as lead, cadmium and copper.
Sources of air pollution refer to the various locations, activities or factors which are responsible for the releasing of pollutants into the atmosphere. These sources can be classified into two major categories which are: 1)Anthropogenic sources (human activity) mostly related to burning different kinds of fuel. 2) Natural sources Dust from natural sources, usually large areas ofland with little or no vegetation.